TRAGIC: Staten Island dad Steven Sierra (left) is on his own with two kids after wife Sarai (middle) went to Turkey and was killed after a tryst with a man known as Tarkan K. (right). (
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The Staten Island mom who had a secret rendezvous the day before she went missing in Turkey had sex with her paramour in the restroom of a bar, local media reported.

Sarai Sierra was found last Saturday beaten to death in Istanbul, two weeks after she didn’t make her flight home.

Her secret lover, identified by Turkish media only as Tarkan K., began communicating with Sierra three or four months ago, his lawyer said.

Ozkan Polat said his client “comes from a good family and completed a master’s program abroad. . . . [He’s] very demoralized.”

The two met online and Sierra, 33, e-mailed him, “I’m coming to Turkey. Can we meet?” Polat told Turkish media.

Tarkan told Istanbul police that they had sex in a bar bathroom in Beyoglu on Jan. 20, Hürriyet newspaper reported. Tarkan has denied wrongdoing and had previously denied the two had a relationship.

The news emerged as the woman’s body on a flight headed home. The body arrived in New York last night.

Her husband and mother met at the Matthew Funeral Home yesterday to plan the burial.

Steven Sierra said he broke the news to their sons. “They were distraught, very emotional,” he said of his 9- and 11-year-old boy soutside the funeral home. “I had to be honest with them, unfortunately. I told them that mommy got hurt . . . and she died.”

Investigators said the woman was last spotted on surveillance tape wearing a coat and carrying a handbag, which were not found with her body, Turkish media reported.

She was not wearing pants — which were found ripped nearby, according to a report.

Steven Sierra asked cops whether his wife had been raped, Hürriyet reported, but there were no obvious signs of sexual assault.

“They’re working right now to solve this case. There’s nothing new to say,” the husband said.

His wife left on her solo European adventure on Jan. 7 and was due to fly back two weeks later, but never returned home.

She was found dead last week from a single blow to the head in the Sarayburnu section of Istanbul.

The FBI — which is investigating the case along with Turkish authorities — has been probing whether Sierra was tied up with a criminal element, a source previously told The Post.

The wake is scheduled for Valentine’s Day, and the funeral will be held the next day.